Conventionally, there are two main input methods used in electronic devices to receive user input: a method based on a full keyboard on which each alphabet key corresponds to one letter, and a method based on a reduced keyboard on which multiple letters can correspond to one key. For example, a nine-square grid keyboard is a reduced keyboard. On the nine-square grid keyboard, the digit keys 1 through 9 are arranged in three rows by three columns. Each of the digit keys 1 through 9 may also correspond to multiple letters.
In the method based on the full keyboard, a user can input a letter by only clicking a corresponding alphabet key.
In the method based on the reduced keyboard, the user can input a letter by clicking a corresponding key multiple times, such that the letters indicated on the key are displayed sequentially, until the letter to be inputted is displayed for the user's selection.
Conventionally, a remote controller having four direction keys, including an up key, a down key, a left key, and a right key, and a confirm key may be used to input letters to a device. For example, a full keyboard or a reduced keyboard is displayed on a screen of the device. The user can select a letter to be inputted through the direction keys, and then confirm the selection by using the confirm key.
However, in both the method based on the full keyboard and the method based on the reduced keyboard, when selecting a state of the inputted character, such as the uppercase state and the lowercase state, the user generally needs to first press a “shift” key or a key having the similar function. When the user inputs a string of characters that needs to switched between the uppercase state and the lowercase state, efficiency of inputting characters will be reduced.